Paper machine quality systems (QCS) are built to last; they are a long-term value investment, to be sure. But, did the original designers really expect these systems would last for decades? Maybe that's a moot point considering the reality today. The lifespan of many of the so-called legacy QCS systems is often being stretched from fifteen to twenty years, or even longer. Data from Fisher International show that there are 54 systems fifteen years or older still operating in Canadian mills.

It's true that many systems have been upgraded with new technology along the way but, in quite a few cases, the original 1980s or 1990s vintage scanners and sensors remain. As a result, the measurement and control capabilities of older paper machines often lag behind newer machines. Furthermore, the parts to keep them running become obsolete, and the cost of service goes up. Worse still, outright failures can cause costly production interruptions.

Leaps and bounds

During the interim, the capabilities of QCS systems have expanded by leaps and bounds. More precise and faster measurements, multi-variable controls, improved CD profilers and extensive process diagnostic capabilities raise the potential for ROI. And revolutionary new measurements like optical caliper, sheet structure and surface properties open up new ways to improve existing paper grades and move forward to new ones.

With recent paper machine closures there are some aftermarket spare parts available from used legacy systems. Admittedly, it is tempting to keep QCS systems going on for a few more years with borrowed parts, but that short-term solution is somewhat like holding back the sea with a finger in the dyke. Furthermore, there are only so many Dutch boys available to hold back the sea and fix the multiple problems that come with age. Many people with the expertise to repair this older technology have left the business or have retired.

Is it time?

Even if these older systems are maintained at a certain level of performance, they will never match the measurement precision, control stability and papermaking results available from a modern system. Few people will debate that. So, is it time to make the commitment to a new QCS? That's not a quick and easy question to answer since it does involve a significant investment which must compete with other capital expenditures.

To justify a new QCS, all the benefits must be added up. Reducing the present service costs is one factor, but not the only one. Future maintenance costs – a factor in the so-called total cost of ownership – has become an important point of evaluation. The future costs have been reduced considerably by intelligent diagnostics which foretell developing problems. These diagnostics, which can be done remotely by suppliers, plus modular plug-in components allow simple proactive maintenance by mill staff, sometimes avoiding on-site supplier service.

The most significant return on investment may come from a specific measurement, control, control actuator, or a combination of all. For instance, moisture profilers are now popular for their energy-saving potential but they work better with more precise on-line measurements and smarter, responsive controls. Multi-variable controls reduce waste after breaks, start-ups and grade changes, thereby adding to machine efficiency. If a mill plans to move to new, more profitable paper grades, new measurements and controls are very important if not essential for the success of the transition. The list of possibilities is compelling.

The bar is raised

Rather than previous investment strategies linking a QCS upgrade to a machine rebuild, the replacement decisions are now often made based on a solid ROI by the QCS alone. The bar measuring system performance has been raised and a significant investment opportunity awaits. If you haven't bought a new QCS in twenty years, prepare for an intriguing sales process. It's still just as fascinating.

Mark Williamson, Journalist Engineer, Thornhill, Ontario
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